[tip: core/rcu] kvm: mmu: page_track: Fix RCU list API usage

[tip: core/rcu] kvm: mmu: page_track: Fix RCU list API usage

[tip-bot2 for Madhuparna Bhowmik]

The following commit has been merged into the core/rcu branch of tip:

Commit-ID:     df9a30fd1f70a757df193acd7396622eee23e527
Gitweb:        https://git.kernel.org/tip/df9a30fd1f70a757df193acd7396622eee23e527
Author:        Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
AuthorDate:    Sun, 12 Jul 2020 18:40:03 +05:30
Committer:     Paul E. McKenney <paulmck@kernel.org>
CommitterDate: Mon, 24 Aug 2020 18:36:23 -07:00

kvm: mmu: page_track: Fix RCU list API usage

Use hlist_for_each_entry_srcu() instead of hlist_for_each_entry_rcu()
as it also checkes if the right lock is held.
Using hlist_for_each_entry_rcu() with a condition argument will not
report the cases where a SRCU protected list is traversed using
rcu_read_lock(). Hence, use hlist_for_each_entry_srcu().

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: <kvm@vger.kernel.org>
---
 arch/x86/kvm/mmu/page_track.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c
index a84a141..8443a67 100644
--- a/arch/x86/kvm/mmu/page_track.c
+++ b/arch/x86/kvm/mmu/page_track.c
@@ -229,7 +229,8 @@ void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
 		return;
 
 	idx = srcu_read_lock(&head->track_srcu);
-	hlist_for_each_entry_rcu(n, &head->track_notifier_list, node)
+	hlist_for_each_entry_srcu(n, &head->track_notifier_list, node,
+				srcu_read_lock_held(&head->track_srcu))
 		if (n->track_write)
 			n->track_write(vcpu, gpa, new, bytes, n);
 	srcu_read_unlock(&head->track_srcu, idx);
@@ -254,7 +255,8 @@ void kvm_page_track_flush_slot(struct kvm *kvm, struct kvm_memory_slot *slot)
 		return;
 
 	idx = srcu_read_lock(&head->track_srcu);
-	hlist_for_each_entry_rcu(n, &head->track_notifier_list, node)
+	hlist_for_each_entry_srcu(n, &head->track_notifier_list, node,
+				srcu_read_lock_held(&head->track_srcu))
 		if (n->track_flush_slot)
 			n->track_flush_slot(kvm, slot, n);
 	srcu_read_unlock(&head->track_srcu, idx);